Arrester element



A. 37, 1948- H. J. BAKER 2,447,048

ARRESTER ELEMENT Filed Jan. 15, 1944 HHZL I E W v g 27 :ITTIIH 26 25/ 27 BEFORE SIZING v AFTER SIZING ,5 HAk FYY T QKER ATTO R N EY Patented Aug; 17, 1948 STS PA QFFICE ARRESTER ELEMENT Harry J. Baker, Speedway, Ind, assignor to Union Carbide and Carbon Corporation, a corporation of New York 2 Claims.

This invention relates to porous type backfire arresters for use in combustible gas systems such as blowpipes, and more particularly to a porous backfire arresting element having a flame defiector therein and to a method of fabricating the same.

It has been found that the porous metal element of such arresters fail over the face area thereof nearest to the discharge passage of the arrester casing. In order to prevent premature destruction of the porous element, it has been proposed to insert a nonporous metal plate or deflector in the porous material which will absorb the shock of a backfire and disperse the flame of a backfire prior to entry into the pores of the porous element. In the fabrication of the porous element itself, the porous material as supplied by the trade does not have a porosity suitable for use with blowpipes and has tobe reworked or compressed to the proper porosity for extinguishing a backfire. Heretofore, the deflectors have been inserted in the porous element after the sizing operation and in such a manner that they are liable to become loose with use.

Objects of the present invention are to provide a porous element for porous type backfire arresters with a deflector which will not become loose with use; and to provide a simple method of securing a nonporous deflector in the porous body of the element and sizing the latter.

According to the present invention, an unsized deflector of solid metal is inserted in an unsized porous metal block. As the block is compressed to size, the deflector is simultaneously upset and caused to fit securely within the sized porous element. The deflector extends axially through the plate, and is reduced to the same length that the porous block is reduced in thickness, leaving its ends flush with opposite faces of the porous element. Advantage is thereby taken of the sizing step in manufacture of the porous element to secure the deflector firmly in place within the porous element.

For other objects and for a better understanding of the invention, reference may be had to the following detailed description taken in connection with the accompanying drawing, in which Fig. l is a cross sectional view of a backfire arrester embodyin the porous arresting element of the present invention,

Fig. 2 is an exploded isometric view of the unsized porous block and of the unsized deflector insert prior to the latter being fitted within its 2 opening in the porous block, with the block being shown in half section,

Fig. 3 illustrates the assembled porous block and insert before the sizing operation,

Fig. 4 is a cross sectional view of the completed porous element.

Referring now particularly to Fig. 1, there is shown a backfire arrester A comprising a casing I!) having a gas inlet passage II and a gas outlet passage I'Z. To the inlet H and outlet l2 there is respectively connected pipe couplings l3 and It. During the operation of a blowpipe for example flashbacks and backfires of the gas strike at a downstream face of a porous element 85. The porous element I5 is retained in a ring it which is clamped between separable parts it and i8 of the casing H3. Such parts ii and 58 are clamped together by bolts i 3.

The normal direction of flow of the combustible gas through the flash arrester A is from the inlet i I through pores of the porous element 85 and outwardly through outlet passage i2 and pipe coupling it. But upon the occurrence of a backfire the flame moves in the reverse direction.

In order that the porous element be not destroyed over the area of the downstream face adjacent the gas outlet passage I 2, it has been proposed to provide in that area a solid or nonporous metal deflector adapted to absorb the shock of a backfire to distribute the flame of a backfire over an enlarged area i. e. over the porous major portion of the disc face to insure its extinguishment.

Referring now to Figs. 2, 3 and 4, according to the invention, a porous arresting element with a deflector is produced by the following method. To start with there is provided an unsized porous metal block 2| of a porosity unsatisfactory for use in a blowpipe and which needs to be com pressed to size. Such porous block may be made by sintering together bronze metal particles,

such material being known to the trade as Porex.

Into the block 2!, there is drilled or otherwise formed during manufacture of the block a central hole or opening 22 consisting of an enlarged portion 23, a narrow portion 25 and a frusto conical portion 25; This opening is such as to receive an unsized deflector insert 25 of solid metal block II in a direction to reduce its thickness and at the same time to upset the solid metal insert 26 so that the enlarged head and shank thereof till all portions of the opening, the end faces of the insert being brought flush with the faces of the disc to provide a deflector II. The porous element II is thus made satisfactory for use in a blowpipe flash arrester and the deflector 20 is made thoroughly secure in direct heat-conductive relation with the porous material. Accordingly, the invention provides a simple method of providing a porous flash arresting element with a flame deflector. From Figs. 3 and 4 of the drawing it may be seen that upon sizing or compressing the arrest-' er and deflector; that the shank "is upset and the porous arrester is compressed tightly around the shank. Since bronze is known to contain a substantial quantity of copper it will be apparent that sintered bronze is heat conductive. The sizing pressure causes the pores to be slightly flattened or deformed compared to the shape of the pores in an unsized disc; The

' shank II of the deflector is compacted more than the metal in the head 21 because the shank is subjected to greater compression per unit of cross sectional area in shortening. A large area of the head 21 is placed under no greater compressive stress than the porous disc. To the extent that the porous material between the engaged ends of the shank may be retained under compression the shank of the deflector is under tension.

This application is an improvement upon the arrester described and claimed in the prior application of Messrs. Olsen and Berger, Serial No. 518,422, filed January 15, 1944.

While detail changes may be made in the con-' struction of and the method of fabricating these porous disc elements, it shall be understood that such changes shall be within the spirit and 4 tered disc with the exposed race of the buttonlike member extending over a substantial part of only the central portion 0! a downstream race of said disc near and not sunk below the adiacent face of said porous disc to receive the impact of and spread any backfire flame arrested in the pores of said sintered metal disc, a shank portion for the button-like member connected thereto for holding the same in place on the disc face, said shank portion extending well into the body or said disc and provided with an anchorage portion of shape in the plane or the disc which is enlarged with respect to that 01 the shank portion and adapted for cooperation with the porous metal to retain the button-like member and shank portion from coming out of the porous disc.

- thereof and having its exposed end substantially scope of the present invention as defined by the flush with said other face, the portion of the shank member adjacent said other face being flared.

HARRY J. BAKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,420,405 Beler June 20, 1922 1,497,197 Schroder June 10, 1924 1,869,260 Jenkins July 26, 1932 2,157,596 I Davis May 9, 1939 2,213,043 Jacobson Aug. 27, 1940 2,267,918 Heldabolt Dec. 30, 1941 FOREIGN PATENTS Number Country Date 548,737 Germany Apr. 18, 1932 

